Use a USB fingerprint reader

For partners with hardware scanners, the SDK talks to a local hardware service running on the user’s workstation. You work with enroll, verify, and search directly; the transport is hidden.

Companion application required

Every contactful (physical-scanner) capture flow requires the SladeID companion application running on the user’s device alongside the browser. The web SDK alone cannot drive USB scanners — the companion app brokers access to the hardware.

• SladeID Android — install from the Google Play Store .
• SladeID Windows — available on request. Contact your Slade ID integration contact.

The browser-only contactless capture flows (Capture a fingerprint, Enroll a face) do not require the companion app.

Prerequisites

• The SladeID companion application running on the workstation, with a compatible scanner attached.
• A token source for the companion service — implement getToken to fetch from your auth service.

Full example

import { createFingerprintReader, HwsError } from '@sladeid/slade-id-sdk';
 
const reader = createFingerprintReader({
  getToken: async () => fetchHwsToken(),
});
 
reader.on('connected', () => console.log('companion app reachable'));
reader.on('device-attached', (d) => console.log('device:', d.name));
reader.on('device-detached', (d) => console.log('removed:', d.id));
 
const session = reader.createEnrollmentSession({
  enrollee: 'subject-123',
  position: 2, // right index
});
 
session.on('ready', () => prompt('Place your finger on the scanner'));
session.on('scanning', () => showSpinner());
 
session.on('captured', (result) => {
  console.log('enrolled, template length', result.template?.length);
});
 
session.on('error', (err) => {
  if (err instanceof HwsError) {
    console.error(err.code, err.correlationId);
  }
});
 
try {
  await session.start();
} finally {
  hideSpinner();
}

What can go wrong

• ConnectionError with code READER_CONNECTION_FAILED — the SladeID companion application isn’t running on the workstation. Ask the user to launch it (Android or Windows, see above).
• DeviceUnavailableError — no reader plugged in, or the reader is in use by another application.
• ReaderAuthError — the token was rejected. Check your getToken implementation and the companion app’s auth configuration.
• BiometricMismatchError — only thrown by the rejection-style helpers. Plain verify() resolves with { matched: false } instead.

See also

• Fingerprint reader reference
• Capture modality